The prairie was short circuiting. At least that's how it looked as hundreds of sparks flew above the milkweed and bluestem in wild, alternating patterns. But the flashes were actually male fireflies, each trying to impress a potential mate with the intensity of his glowing belly. That was my guess, anyway, as I watched the light show at the edge of an Afton grassland in June. Everywhere I looked that night, male lightning bugs hovered and blinked. Their female counterparts perched on vegetation below. When the ladies liked what they saw, they responded with their own pops of cool white light.
A few weeks later, I got in touch with Eric Middleton, a Ph.D. candidate in the University of Minnesota's entomology department. Middleton is a firefly fanatic who in July hosted a public event at the Minnesota Landscape Arboretum to talk about his favorite insect. I was curious if it had been a better than average summer for the bioluminescent beetles, or if the fireworks I saw out in Afton were the exception to the rule.
"I do think there is some anecdotal evidence that this year is pretty good for fireflies," wrote Middleton in an email. "While there seems to be a general downward trend in firefly sightings as time goes on, no one I talked to thought this year was particularly bad, and several said it was a notably better year."
The entomologist added that our unusually wet spring might explain the increased sightings, as firefly larvae tend to fare better in damp environments. He also confirmed my armchair hypothesis about the mating dance.
Though threatened by light pollution, pesticides, and loss of habitat, fireflies remain an enchanting sign of seasonal change. For this reason they're a favorite of phenologists—those who observe the "rhythmic biological nature of events as they relate to climate." Minnesota naturalist John Latimer uses that definition on his popular phenology-themed radio show, which broadcasts each Tuesday morning on KAXE out of Grand Rapids. A friend of mine introduced me to the show, and to phenology in general, a few years ago. One radio segment in July found the host bemoaning the arrival of deer flies. To combat the biting buggers, Latimer suggested putting a feather in your hat when outdoors, as flies "tend to circle the highest point."
Latimer is one of a handful of Minnesotans who have spent decades observing and reporting the state's seasonal shifts. Another is Larry Weber, who is profiled on page 40. Like Latimer, Weber has a radio show—Backyard Almanac on KUMD in Duluth—where he explains things such as why goldfinches tend to be late nesters. (They wait for thistle to mature so they can use it to build their homes.)
We're lucky to have not one, but two, celebrity phenologists in Minnesota. Their observations will become even more valuable as our climate continues to warm. But you don't have to be an expert to study phenology. Simply go outside and observe the changes you see through the seasons. If you're feeling ambitious, submit your findings to Nature's Notebook, a citizen science website run by the USA National Phenology Network. Or better yet, shoot us a note. One of the true joys of my job is hearing from readers about the daily dramas playing out in their own backyards. Speaking of which, did you see more fireflies than usual this summer? If so, let me know. We can trade notes—and I can keep bragging about that light show I saw in Afton. It really was amazing.